The invention relates to a coating material in laminate form intended in insulation systems for installation elements such as pipes, containers and ventilation ducts. The invention also relates to an insulation system comprising such a coating material.
In the technical fields of buildings and processes, it is common practice to insulate, for example, pipes and containers. The insulation may be provided in shell form, for pipes, or in the form of panels or mats. A typical insulation is made up of a thermally insulating material, such as mineral wool, which, on its side turned toward the external environment, is provided with a protective outer layer made of plastic, paper or metal, and laminated onto said material. The protective outer layer conventionally has a very small thickness. When this consists of aluminum, the thickness is around 18 μm, which is regarded as the lower limit for an aluminum foil resistant to diffusion. This small thickness means that the outer layer is, however, subject to mechanical damage which may occur, for example, during fitting or maintenance. One standard way of increasing its strength is to provide the outer layer with a reinforcement, for example glass fibers embedded in the outer layer. However, such reinforcement is insufficient to give the outer layer of the insulation the required mechanical properties. Good mechanical properties are important, for example, as regards maintenance, insofar as the insulating surface may, in many cases, be the only support surface available, for example for a ladder. The mechanical properties are also important in confined spaces where there is a substantial risk of a person knocking against the outer layer and damaging it.
In cases where the insulations described above consist of a pipe shell, said shell has, for fitting reasons, a slit which allows it be easily opened and fitted over a pipe. The slit is then sealed by means of a band of adhesive tape for example, just like the joints between the adjacent elements. Examples of such pipe shells and the way they are fitted are indicated for example in document U.S. Pat. No. 4,606,957. In the case in which mats are used, a corresponding sealing operation is performed by means of an adhesive tape or a sheet provided with adhesive.
When such sealing is considered as being insufficient, the insulation may, in accordance with document EP 0 308 191, be provided with adhesion-promoting surfaces in combination with an adhesive tape adapted for this purpose.
To increase the mechanical properties while ensuring satisfactory sealing, it is very commonly appropriate to supplement such insulations during fitting with an outer shell. This shell may for example consist of molded, plastic or metal, coverings that are rigid, but always flexible. The joints that are formed between the coverings are sealed for example by means of an adhesive tape or a sheet of the same type of material as the coverings. In the case in which the insulation takes place on surfaces exposed to condensation, a condensation-impervious means must be placed inside such a covering.
It should be noted that the work undertaken by the person carrying out the sealing operation is demanding, in order to provide a satisfactory result. In many cases, the work is complicated, partly because the pipes and the containers are often of complex shape and extent and partly because accessibility is often limited. In addition, the quality of the adhesion during on-site fitting and operation is often insufficient because of the salty or humid environment.
The metal coverings used, for example those available under the brand name ALUPAK®, or in general those termed “stucco sheet”, are formed from pure aluminum with a thickness of 0.1−0.2 mm, which is pressed to the desired shape. There is a manifest risk of causing damage during handling by cuts. In addition, the tear strength is insufficient. The use of coverings made of plastic, available for example under the brand name Isogenopak®, are less advantageous from the standpoint of fire resistance.
The technique described here is the same whether the surfaces are cold surfaces, exposed to condensation, or are hot surfaces, not exposed to condensation.
An estimate in this sector of activity indicates that about 90 to 95% of all insulations are combined with a separate outer layer in covering form, for example as described above. Consequently, this means that in this case there is twice the amount of fitting work, which is expensive and time-consuming, and entails a high risk of surface defects or even integral defects.